Bushings are often thin sleeves made of a strong material inserted into a housing to provide a rotating element some support or to reinforce a piece having insufficient mechanical properties. For example, in a piece made of plastic, subject to abrasion or corrosion, a non abrasive or non corrosive metal bushing may be slid into a hole into the piece of plastic to provide local reinforced material properties. FIG. 8 shows for example such a piece 200 where a bushing 100 is inserted in an opening 201 for providing local reinforcement.
Bushing are defined and purchased generally based on their internal diameters (ID), their external or outer diameters (OD), their length (L) and their material. The SAE numbering system for bushings as a sleeve is in the format of −XXYY-ZZ, where XX is ID in sixteenths of an inch, YY is the OD also in sixteenth of an inch, and ZZ is the length in eights of an inch.
There are different types of bushings, including a solid sleeve bushing, split bushings, cut bushings, flanged bushing, clenched bushing, etc. While the technology shown in the figures of this disclosure shown the new technology on a clenched bushing, one of ordinary skill in the art will understand that the concepts shown and disclosed herein, if possible could be used for any type of sleeve, bushing, or bearing when applicable. Further, this technology equally applies to two or three piece bushings.
In one piece of art, a yoke can be manufactured as a cylinder made from a flat piece of metal rolled in form. Each end of the sheet can include dovetails created using a punch. In the art, what is known is the use of convexities as dovetails (S-shaped) where the tip of the dovetail is wider than the neck of the dovetail to which the tip is inserted. Wider tips allow for the dovetails to remain mated in place even if the structure tries to open. One clear disadvantage is that the dovetails of adjacent surfaces cannot slide into each other on a plane. In the case of a large yoke, the dovetails are bent into shape along with the body of the yoke. What is then known is how specific portions of the border portions of each dovetails are punched and widened locally once the large tip of the dovetails has been slid pass the neck of the dovetails.
In the art of the production of bushings, what are needed is the manufacture of bushings, pieces with bushings, and methods of producing bushings using greater simplicity in execution, where less industrial operations are needed. Further, the method must allow for the creation of varied types and size of bushings using a very modular technology.
One way to work metal where operations to the metal such as punching, coining, bending are needed is the progressive stamping method. In this technology, a flat strip of raw metal is fed using an automatic system through stations where at each station, one or more operations are performed until a finished product is made. At the final station of the technology, generally a cutoff operation separates the finished part from the carrying web. While the progressive stamping method is quick and easy to use, it requires dies and tooling and may not be adapted to the creation of curved or rounded items as each station is done on a plane. What is needed is a method of using this technology to created efficiently and cheaply bushings from a carrying web.